Functional diversity of nanohaloarchaea within xylan-degrading consortia.

Extremely halophilic representatives of the phylum Nanohaloarchaeota (members of the DPANN superphyla) are obligately associated with extremely halophilic archaea of the phylum (according to the GTDB taxonomy). Using culture-independent molecular techniques, their presence in various hypersaline ecosystems around the world has been confirmed over the past decade. However, the vast majority of nanohaloarchaea remain uncultivated, and thus their metabolic capabilities and ecophysiology are currently poorly understood.

Nanohaloarchaea as beneficiaries of xylan degradation by haloarchaea.

Climate change, desertification, salinisation of soils and the changing hydrology of the Earth are creating or modifying microbial habitats at all scales including the oceans, saline groundwaters and brine lakes. In environments that are saline or hypersaline, the biodegradation of recalcitrant plant and animal polysaccharides can be inhibited by salt-induced microbial stress and/or by limitation of the metabolic capabilities of halophilic microbes. We recently demonstrated that the chitinolytic haloarchaeon Halomicrobium can serve as the host for an ectosymbiont, nanohaloarchaeon 'Candidatus Nanohalobium constans'.

Natranaeroarchaeum sulfidigenes gen. nov., sp. nov., carbohydrate-utilizing sulfur-respiring haloarchaeon from hypersaline soda lakes, a member of a new family Natronoarchaeaceae fam. nov. in the order Halobacteriales.

A pure culture of alkaliphilic haloarchaeon strain AArc-S capable of anaerobic growth by carbohydrate-dependent sulfur respiration was obtained from hypersaline lakes in southwestern Siberia. According to phylogenetic analysis, AArc-S formed a new genus level branch most related to the genus Natronoarchaeum in the order Halobacteriales. The strain is facultatively anaerobic with strictly respiratory metabolism growing either by anaerobic respiration with elemental sulfur and thiosulfate as the electron acceptors or by aerobic respiration at microoxic conditions.

Anaerobic carboxydotrophy in sulfur-respiring haloarchaea from hypersaline lakes.

Anaerobic carboxydotrophy is a widespread catabolic trait in bacteria, with two dominant pathways: hydrogenogenic and acetogenic. The marginal mode by direct oxidation to CO using an external e-acceptor has only a few examples. Use of sulfidic sediments from two types of hypersaline lakes in anaerobic enrichments with CO as an e-donor and elemental sulfur as an e-acceptor led to isolation of two pure cultures of anaerobic carboxydotrophs belonging to two genera of sulfur-reducing haloarchaea: Halanaeroarchaeum sp.

Cultivation of a vampire: 'Candidatus Absconditicoccus praedator'.

Halorhodospira halophila, one of the most-xerophilic halophiles, inhabits biophysically stressful and energetically expensive, salt-saturated alkaline brines. Here, we report an additional stress factor that is biotic: a diminutive Candidate-Phyla-Radiation bacterium, that we named 'Ca. Absconditicoccus praedator' M39-6, which predates H.

Halapricum desulfuricans sp. nov., carbohydrate-utilizing, sulfur-respiring haloarchaea from hypersaline lakes.

Nine pure cultures of neutrophilic haloaloarchaea capable of anaerobic growth by carbohydrate-dependent sulfur respiration were isolated from hypersaline lakes in southwestern Siberia and southern Russia. According to phylogenomic analysis the isolates were closely related to each other and formed a new species within the genus Halapricum (family Haloarculaceae). They have three types of catabolism: fermentative, resulting in H formation; anaerobic respiration using sulfur compounds as e-acceptors and aerobic respiration.

Carbohydrate-dependent sulfur respiration in halo(alkali)philic archaea.

Archaea are environmentally ubiquitous on Earth, and their extremophilic and metabolically versatile phenotypes make them useful as model systems for astrobiology. Here, we reveal a new functional group of halo(natrono)archaea able to utilize alpha-d-glucans (amylopectin, amylose and glycogen), sugars, and glycerol as electron donors and carbon sources for sulfur respiration. They are facultative anaerobes enriched from hypersaline sediments with either amylopectin, glucose or glycerol as electron/carbon sources and elemental sulfur as the terminal electron acceptor.

Symbiosis between nanohaloarchaeon and haloarchaeon is based on utilization of different polysaccharides.

Nano-sized archaeota, with their small genomes and limited metabolic capabilities, are known to associate with other microbes, thereby compensating for their own auxotrophies. These diminutive and yet ubiquitous organisms thrive in hypersaline habitats that they share with haloarchaea. Here, we reveal the genetic and physiological nature of a nanohaloarchaeon-haloarchaeon association, with both microbes obtained from a solar saltern and reproducibly cultivated together in vitro.

Reclassification of the genus : proposal of two new genera, gen. nov. to accommodate and gen. nov. to accommodate and .

The genus , currently including four species, is a member of the order , class and consists of obligately alkaliphilic and extremely halophilic members found exclusively in highly alkaline hypersaline soda lakes. The species were classified into this genus mostly based on phylogenetic analysis of the 16S rRNA gene. However, a more advanced phylogenomic reconstruction based on 122 conserved single-copy archaeal protein markers clearly indicates a polyphyletic origin of the species included into this genus, thus warranting its reclassification into three separate genera.

sp. nov. and gen. nov., sp. nov., the first sulfur-respiring alkaliphilic haloarchaea from hypersaline alkaline lakes.

Eight pure cultures of alkaliphilic haloaloarchaea capable of growth by dissimilatory sulfur reduction (previously only shown for neutrophilic haloarchaea) were isolated from hypersaline alkaline lakes in different geographic locations. These anaerobic enrichments, inoculated with sediments and brines, used formate, butyrate and peptone as electron donors and elemental sulfur as an electron acceptor 4 M total Na and at pH 9-10. According to 16S rRNA gene sequencing, the isolates fell into two distinct groups.

Author Correction: The discovery of Lake Hephaestus, the youngest athalassohaline deep-sea formation on Earth.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

The discovery of Lake Hephaestus, the youngest athalassohaline deep-sea formation on Earth.

Hydrated, magnesium-rich minerals and subglacial brines exist on the martian surface, so the habitability of high-Mg environments on Earth has extraterrestrial (as well as terrestrial) implications. Here, we report the discovery of a MgCl-dominated (4.72 M) brine lake on the floor of the Mediterranean Ridge that underlies a 3500-m water column, and name it Lake Hephaestus.

Sulfur Respiration in a Group of Facultatively Anaerobic Natronoarchaea Ubiquitous in Hypersaline Soda Lakes.

The ubiquity of strictly anaerobic sulfur-respiring haloarchaea in hypersaline systems with circumneutral pH has shaken a traditional concept of this group as predominantly aerobic heterotrophs. Here, we demonstrated that this functional group of haloarchaea also has its representatives in hypersaline alkaline lakes. Sediments from various hypersaline soda lakes showed high activity of sulfur reduction only partially inhibited by antibiotics.

Discovery of anaerobic lithoheterotrophic haloarchaea, ubiquitous in hypersaline habitats.

Hypersaline anoxic habitats harbour numerous novel uncultured archaea whose metabolic and ecological roles remain to be elucidated. Until recently, it was believed that energy generation via dissimilatory reduction of sulfur compounds is not functional at salt saturation conditions. Recent discovery of the strictly anaerobic acetotrophic Halanaeroarchaeum compels to change both this assumption and the traditional view on haloarchaea as aerobic heterotrophs.

Complete genome sequence of 'Halanaeroarchaeum sulfurireducens' M27-SA2, a sulfur-reducing and acetate-oxidizing haloarchaeon from the deep-sea hypersaline anoxic lake Medee.

Strain M27-SA2 was isolated from the deep-sea salt-saturated anoxic lake Medee, which represents one of the most hostile extreme environments on our planet. On the basis of physiological studies and phylogenetic positioning this extremely halophilic euryarchaeon belongs to a novel genus 'Halanaeroarchaeum' within the family Halobacteriaceae. All members of this genus cultivated so far are strict anaerobes using acetate as the sole carbon and energy source and elemental sulfur as electron acceptor.

Genome sequence of obligate marine polycyclic aromatic hydrocarbons-degrading bacterium Cycloclasticus sp. 78-ME, isolated from petroleum deposits of the sunken tanker Amoco Milford Haven, Mediterranean Sea.

Cycloclasticus sp. 78-ME isolated from petroleum deposits of the sunken tanker “Amoco Milford Haven” (Gulf of Genoa, Ligurian Sea, Italy) could effectively degrade polycyclic aromatic hydrocarbons of up to five condensed rings. The genome of 78-ME was sequenced and analysed to gain insights into its remarkable degrading capacities.

Elemental sulfur and acetate can support life of a novel strictly anaerobic haloarchaeon.

Archaea domain is comprised of many versatile taxa that often colonize extreme habitats. Here, we report the discovery of strictly anaerobic extremely halophilic euryarchaeon, capable of obtaining energy by dissimilatory reduction of elemental sulfur using acetate as the only electron donor and forming sulfide and CO2 as the only products. This type of respiration has never been observed in hypersaline anoxic habitats and is the first example of such metabolic capability in the entire Archaea domain.

Microbial community of the deep-sea brine Lake Kryos seawater-brine interface is active below the chaotropicity limit of life as revealed by recovery of mRNA.

Within the complex of deep, hypersaline anoxic lakes (DHALs) of the Mediterranean Ridge, we identified a new, unexplored DHAL and named it 'Lake Kryos' after a nearby depression. This lake is filled with magnesium chloride (MgCl2 )-rich, athalassohaline brine (salinity > 470 practical salinity units), presumably formed by the dissolution of Messinian bischofite. Compared with the DHAL Discovery, it contains elevated concentrations of kosmotropic sodium and sulfate ions, which are capable of reducing the net chaotropicily of MgCl2 -rich solutions.

A Three-Component Microbial Consortium from Deep-Sea Salt-Saturated Anoxic Lake Thetis Links Anaerobic Glycine Betaine Degradation with Methanogenesis.

Microbial communities inhabiting the deep-sea salt-saturated anoxic lakes of the Eastern Mediterranean operate under harsh physical-chemical conditions that are incompatible with the lifestyle of common marine microorganisms. Here, we investigated a stable three-component microbial consortium obtained from the brine of the recently discovered deep-sea salt-saturated Lake Thetis. The trophic network of this consortium, established at salinities up to 240, relies on fermentative decomposition of common osmoprotectant glycine betaine (GB).

Comparative analysis of deep-sea bacterioplankton OMICS revealed the occurrence of habitat-specific genomic attributes.

Bathyal aphotic ocean represents the largest biotope on our planet, which sustains highly diverse but low-density microbial communities, with yet untapped genomic attributes, potentially useful for discovery of new biomolecules, industrial enzymes and pathways. In the last two decades, culture-independent approaches of high-throughput sequencing have provided new insights into structure and function of marine bacterioplankton, leading to unprecedented opportunities to accurately characterize microbial communities and their interactions with the environments. In the present review we focused on the analysis of relatively few deep-sea OMICS studies, completed thus far, to find the specific genomic patterns determining the lifeway and adaptation mechanisms of prokaryotes thriving in the dark deep ocean below the depth of 1000m.

The gut microbiota of larvae of Rhynchophorus ferrugineus Oliver (Coleoptera: Curculionidae).

Background: The red palm weevil (RPW) Rhynchophorus ferrugineus Olivier (Coleoptera: Curculionidae) is one of the major pests of palms. The larvae bore into the palm trunk and feed on the palm tender tissues and sap, leading the host tree to death. The gut microbiota of insects plays a remarkable role in the host life and understanding the relationship dynamics between insects and their microbiota may improve the biological control of insect pests.

Microbial life in the Lake Medee, the largest deep-sea salt-saturated formation.

Deep-sea hypersaline anoxic lakes (DHALs) of the Eastern Mediterranean represent some of the most hostile environments on our planet. We investigated microbial life in the recently discovered Lake Medee, the largest DHAL found to-date. Medee has two unique features: a complex geobiochemical stratification and an absence of chemolithoautotrophic Epsilonproteobacteria, which usually play the primary role in dark bicarbonate assimilation in DHALs interfaces.

Gene sets for utilization of primary and secondary nutrition supplies in the distal gut of endangered Iberian lynx.

Recent studies have indicated the existence of an extensive trans-genomic trans-mural co-metabolism between gut microbes and animal hosts that is diet-, host phylogeny- and provenance-influenced. Here, we analyzed the biodiversity at the level of small subunit rRNA gene sequence and the metabolic composition of 18 Mbp of consensus metagenome sequences and activity characteristics of bacterial intra-cellular extracts, in wild Iberian lynx (Lynx pardinus) fecal samples. Bacterial signatures (14.

Metagenomic analysis of hadopelagic microbial assemblages thriving at the deepest part of Mediterranean Sea, Matapan-Vavilov Deep.

The marine pelagic zone situated > 200 m below the sea level (bls) is the largest marine subsystem, comprising more than two-thirds of the oceanic volume. At the same time, it is one of the least explored ecosystems on Earth. Few large-scale environmental genomics studies have been undertaken to examine the phylogenetic diversity and functional gene repertoire of planktonic microbes present in mesopelagic and bathypelagic environments.